In particular in driving or putting down big-hole wells, drilling fluid is supplied to the well during the drilling operation. The drilling fluid serves on the one hand to lubricate the drilling tools working at the well face and/or at the bottom hole as well as the support of the drift face and/or the bore surface. On the other hand, with the help of the drilling fluid, loosened drilling chips can also be removed from the well by, for example, supplying fresh drilling fluid in the area of the well face and/or the bottom hole through a hollow drill string, thereby creating a stream of drilling fluid which entrains loosened drill chips and removes the debris from the well.
To create the drilling fluid flow, which is required for such removal, particularly high-performance pump systems are required. The flow rate of such pump systems is usually in the range of maximum 3000 L/min at a pressure of maximum 500 bar.
State-of-the-art pump systems are characterized by a particularly compact design because the rotary drive device of the pump system driving the pump unit is situated above the pump unit and is flange-mounted on the top side of the housing. The rotary drive devices usually have a power level of up to 1700 kW.
To be able to transmit this power and/or the torque supplied by the rotary drive device to the input shaft of the pump unit, it is known that both the shaft of the rotary drive and the drive shaft of the pump may lead out of the respective housing on both sides, so that each shaft has two shaft ends. A chain wheel is mounted in a rotationally fixed mount on each shaft end. The torque is thus transmitted through two chains running parallel to one another.
One disadvantage with such pump systems is that the structural complexity required because of chains running on both sides and the need for components in duplicate and in particular the four-fold shaft bushings required with corresponding sealing arrangements is high. Furthermore, the chain drives create a substantial noise level during operation.